Winding mandrel

ABSTRACT

A winding mandrel assembly for holding a plurality of coil bobbins while electrical coils are wound thereon, including a plurality of individual bobbin holders or mandrels telescoped over a common shaft member. Each bobbin mandrel axially locates one end of its associated coil bobbin, and one end of a coil bobbin on an adjacent bobbin mandrel. One end of each bobbin mandrel extends into a depression in the end of the next adjacent bobbin mandrel, to locate and properly support the ends of the coil bobbins while compensating for dimensional tolerances in the length of the coil bobbins.

United States Patent Petrinjak et al.

[4 1 Jan. 18, 1972 [54] WINDING MANDREL 2,526,029 /1950 Judelson ..242/68 X 2,815,905 12/1957 Birchler et al. ...242/7.1l X [721 lmemms- E i Masury 2,946,096 7/1960 Stahl ..242/1 18.7 x

llam J. Graslnger, Stoneboro, Pa.

[73] Assignee: Westinghouse Electric Corporation, Pitt- FOREIGN PATENTS OR APPLICATIONS g 771,403 4/1957 Great Britain ..242/7.13 [22] Filed: 1969 Primary Examiner-Stanley N. Gilreath [21] App]. No.: 889,509 Attorney-14. T. Stratton, F, E. Browder and Donald R.

Lackey [52] [1.5. CL; ..242/1, 242/7.1i, 242/ R, 57 ABSTRACT 242 59 A winding mandrel assembly for holding a plurality of coil 51 1111.01. ..Bh 54 00, B65h 55/00 bobbins while electrical coils are Wound thereonincluding a 58 Field of Search ..242 1, 7.09, 7.1 1, 7.13, 56.9, plurality of individual bobbin'holders or mandrels leleswped 242/68 84 11 4 118], 2 5 355 R 1295 130 over 3. common shaft member. Each bobbin mandrel axially 159 166 locates one end of its associated coil bobbin, and one end of a coil bobbin on an adjacent bobbin mandrel. One end of each [56] References Cited bobbin mandrel extends into a depression in the end of the next adjacent bobbin mandrel, to locate and properly support UNITED STATES PATENTS the ends of the coil bobbins while compensating for dimensional tolerances in the length of the coil bobbins. 358,705 3/1887 Smith.... ..242/1 18.41 2,388,598 1 1/1945 Cahill ..242/7.09 UX 1 Claims, 6 Drawing Figures 7 E 32\F F I F 62\ i i so 3 92 Q Q f 6'4 &' I H WINDING MANDREL BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates in general to windingmandrels, and more specifically to a winding mandrel assembly for supporting a plurality of coil bobbins while electrical coils are wound thereon.

2. Description of the Prior Art It is common in the prior art to hold a plurality of coil bobbins for winding coils thereon,- with a mandrel which includes two wedge-shaped halves. The coil bobbins are placed in locating depressions on one of the mandrel halves, and then the other half is insertedthrough the openings in the coil bobbins to mate with the first half. In order to obtain the desired holding action, one end of the second mandrel half is pounded into axial alignment with the first half, tightly holding thecoil bobbins when the combined dimensions of the the Womandrel halves increase to that of one of the dimensions of the opening in the coil bobbins. The frictional forces developed on the flange members of the coil bobbins, however, both during assembly and disassembly, are often of sufiicient magnitude to cause the flange members to break away from the tubular connecting portion of the coil bobbin, resulting in costly scrap and delays in production. Further, the flange members are not circumferentially supported while the coils are being wound thereon, often resulting in the coil wire pushing the flange members outwardly as the coil build dimension grows.

Thus, it would be desirable to provide a new and improved winding mandrel assembly for holding a plurality of coil bobbins, which assembly does not subject the coil bobbins to the wedging action of a split mandrel, and which provides uniform circumferential support for the flange members of the coil bobbin. Further, these features should not be provided at the expense of increasing the assembly and disassembly time of the coil bobbins and the winding mandrel.

SUMMARY OF THE INVENTION Briefly, the present invention is a new and improved winding mandrel assembly which includes a shaft member, and a plurality of individual coil bobbin holders or mandrels, each of which have first and second ends and an opening which extends between its ends. Each bobbin mandrel holds a coil bobbin and includes a circumferential stop located between its ends which locates and provides uniform circumferential support for one of the flange members of its associated coil bobbin. The bobbin mandrels and coil bobbins are telescoped over the shaft member, with the first end of one bobbin mandrel locating and providing circumferential support for the flange member of a coil bobbin disposed on an adjacent mandrel. The second end of each bobbin mandrel enters a depression in the first end of the next adjacent bobbin mandrel, to enable the flange members of the coil bobbins to be uniformly supported while compensating for differences in the longitudinal dimensions of the coil bobbins.

BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and uses of the invention will become more apparent when considered in view of the following detailed description and drawings, in which:

FIG. 1 is an elevational view, in section, of a winding mandrel constructed according to the teachings of the prior art;

FIG. 2 is an elevational view of a shaft and nut assembly for use in a winding mandrel constructed according to the teachings of the invention;

FIG. 3 and 3A are elevational and end views, respectively, of a bobbin mandrel for use in a winding mandrel assembly constructed according to the teachings of the invention;

FIG. 4 is a fragmentary perspective view illustrating the assembly of a coil bobbin on the shaft member and bobbin mandrel shown in FIGS. 2 and 3; and

FIG. 5 is a fragmentary elevational view, in section, of a completed winding mandrel assembly constructed according to the teachings of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and FIG. I in particular, there is shown an elevational view, in section, of a winding mandrel assembly 10 constructed according to the teachings of the prior art. Winding mandrel'assembly 10 includes first and second mating wedge-shaped sections or portions 12- and 14, respectively. A plurality of coiIbobbins, such as coil-bobbins 16, 18 and 20 are disposed on the first wedge-shaped section 12, axially spaced and located in the depressions 22, 24 and 26, respectively. Each of the coil bobbins, such as coil bobbin 16, includes a tubular insulating member 28 having an opening 31 which extends between its ends, about which electrical coils are wound, and first and second insulating flange members 30 and 32, respectively, which are fixed to the ends of the tubular member 28, such as by gluing. Flange members 30 and 32 have openings therein which are in communication with the opening 31 in the tubular member 28, and one or more of the flange members may include electrical terminals to which the ends of certain of the coils may be connected after winding. After the plurality of coil bobbins are placed on the first wedge-shaped section 12, the second wedge-shaped section 14 is inserted through the openings in the coil bobbins with their complementary wedge surfaces in sliding contact, until the ends of the two wedge-shaped sections are aligned. This process increases the dimension X of the mandrel 10 to that one of the dimensions of the substantially rectangular openings in the coil bobbins, to securely hold the coil bobbins while the mandrel I0 is held by the spindles of a winding machine and coils are wound simultaneously on all of the coil bobbins. However, in order to obtain the tight holding action required, the lasty to 1 inch of travel of the second wedgeshaped section 14, to produce alignment between the ends of the wedge-shaped sections, often requires that an end of one of the wedge-shaped sections be struck with a mallet while the opposite end of the other wedge-shaped section is fixed. Thus, sliding frictional forces are developed between the second wedge-shaped section 14 and the various flange members of the coil bobbins, which forces may be sufficient to break the adhesive bond between the flange members and their associated tubular portions. This breaking away of the flange members from the tubular member may occur either during assembly of the mandrel, prior to winding the electrical coils, or during disassembly after the coils are wound. In either event, costly scrap is generated, especially if the coils have been wound on the coil bobbins. Redesigning the coil bobbins to eliminate frictional contact between the sliding mandrel halves and the inner edges of the flange members, such that the flange members encircle and contact the outer surface of the tubular members, instead of being connected to the extreme ends thereof, is not a practical solution to the problem as this bobbin design presents difficult problems in the manufacture of the coil bobbins, as disclosed in our copending application Ser. No. 857,962, filed Sept. 15, 1969 which application is assigned to the same assignee as the present application.

Mandrel 10 also has other disadvantages. For example, the flange members of the coil bobbins are only axially supported on one side of their substantially rectangular openings, and if the dimensional tolerance of the longitudinal dimension of the coil bobbins is great enough, axial support on even this one side of the opening will be provided only when the coil bobbins snugly fit the depressions in the first wedge-shaped section 12.

The present invention is a new and improved winding mandrel assembly for holding a plurality of coil bobbins while winding electrical coils thereon, which includes a shaft member, shown in FIG. 2, and a plurality of individual bobbin holders or mandrels, shown in FIG. 3. Specifically, FIG. 2 is an elevational view of a shaft member 40 formed of a suitable material such as steel, having first and second ends 42 and 44, respectively, adapted to be held by the spindles of a coil-winding machine, such as by having openings 46 and 48 disposed in its first and second ends, respectively, which are adapted to receive the spindles of the winding machine. Threads 50 are disposed on shaft 40 adjacent end 44 thereof, which are adapted to threadably engage a nut member 52. Shaft member 40, except for its threaded portion 50, has a substantially rectangular cross-sectional configuration, and has a substantially rectangularly shaped projection 54 which starts a short distance from its end 42 and extends for a predetermined longitudinal dimension, such as /5 to it of an inch. The dimension 1.. of shaft 40 between projection 54 and the start of the threaded portion 50 is determined by the number of coil bobbins to be disposed thereon, the required spacing between adjacent coil bobbins, and the longitudinal dimensions of the coil bobbins.

FIGS. 3 and 3A are elevational and end views, respectively, of a bobbin mandrel or holder 60, formed of a suitable material, such as aluminum, which is dimensioned to hold an individual coil bobbin. Thus, as many bobbin mandrels 60 will be required as there are positions on the winding machine. For example, if coils are to be simultaneously wound on the winding machine, 10 bobbin mandrels or holders 60 will be required for each winding mandrel assembly.

Each bobbin mandrel 60 has first and second ends 62 and 64, respectively, and a substantially rectangular opening 66 which extends between its ends. The portion of shaft 40 indicated by dimension L and the opening 66 in bobbin mandrel 66 have dimension selected to enable the bobbin mandrel 60 to be telescoped onto the shaft 40, with a close but easily slida ble fit. Each bobbin mandrel 60 also has first and second axially adjacent rectangular portions 68 and 70, with the outer dimensions of the first rectangular portion 68 exceeding those of the second rectangular portion 70 by a predetermined amount, to provide a continuous circumferential step or shoulder 72 at the junction of the two axially adjacent portions. The longitudinal or axial dimension 74 of the first portion 68 is selected to provide the desired spacing between adjacent coil bobbins, while the axial dimension 76 of the second portion 70 is selected to be at least as long as the longest longitudinal dimension of the coil bobbins, including its maximum tolerance. Dimension 76 preferably slightly exceeds the maximum longitudinal dimension of the coil bobbins, for purposes which will be hereinafter explained.

The outer dimensions of the second rectangular portion 70 are selected to snugly but smoothly allow a coil bobbin to be telescoped thereon, and the outer dimensions of the first rectangular portion 68 are selected to provide the desired circumferential support for the flange members of the coil bobbins required to support the flanges while the electrical coils are being wound on the coil bobbins.

When the bobbin mandrels 60, along with their associated coil bobbins, are disposed on shaft 40 with similar orientation, the step or shoulder 72 provides circumferential support for one of the flanges of the coil bobbin disposed on that particular bobbin mandrel, while the first end 62 of the next adjacent bobbin mandrel provides circumferential support for the other flange member of that coil bobbin. Uniform axial support for the flange members, however, would require that all of the coil bobbins have exactly the same longitudinal dimension. Since this is not practical in production, each bobbin mandrel includes a uniform depression in its first end 62 of predetermined depth 82, which depression surrounds the entrance to opening 66, and which has a substantially rectangular crosssectional configuration sized to snugly but slidably receive the second end 64 of the next adjacent bobbin mandrel, when the bobbin mandrels are assembled on shaft 40. Thus, end 62 of the bobbin mandrel 60, which end provides axial support for a flange member of the coil bobbin, is reduced in area to that portion of the end between the outer limits of the depression 80 and the outer surface of the first axial portion 68 of the bobbin mandrel. This is clearly shown in FIG. 3A, which is an end view of bobbin mandrel 60 taken in the direction of arrow 84. The projection 54 on shaft 40 is dimensioned to enter the depression 80 of the first bobbin mandrel to be telescoped over the shaft, and provide a locating stop for the first bobbin mandrel.

In the assembly of the winding mandrel according to the teachings of the invention, the coil bobbins may be telescoped over a bobbin mandrel, and the bobbin mandrel then telescoped over the shaft 40, or the bobbin mandrel 60 may be telescoped over the shaft 40 and the coil bobbin dropped over the shaft and onto the already assembled bobbin mandrel. FIG. 4 is a fragmentary perspective view of a winding mandrel 90 in the process of being assembled, and FIG. 5 is an elevational view, in section, of winding mandrel 90 after assembly has been completed. Like reference numerals in FIGS. 2, 3, 4 and 5 indicate like components, with like reference numerals and a prime mark being used to indicate additional like components within a Figure.

More specifically, bobbin mandrel 60 is telescoped over shaft 40 such that the depression in its first end 62 is against the stop or rectangular projection 54, and then a coil bobbin, such as coil bobbin 16 shown in FIG. 1, is telescoped over the bobbin mandrel 60 with a predetermined longitudinal orientation, such as with its larger flange member 30 against the shoulder 72 of bobbin mandrel 60. Then, a second bobbin mandrel 60' is telescoped over shaft 40, orientated similar to the orientation of the first bobbin mandrel 60. The second end 64 of bobbin mandrel 60 enters the depression 80' of the second bobbin mandrel 60', and the first end 62' of the second bobbin mandrel 60 provides complete circumferential support for flange member 32 adjacent its opening, while complete circumferential support for flange member 30 is provided by the shoulder 72 on its associated bobbin mandrel 60. Therefore, as best shown in FIG. 5, coil bobbin [6 is snugly held between shoulder 72 of bobbin mandrel 60 and the first end 62 of bobbin mandrel 60', with dimensional tolerances on the length of the coil bobbin being taken up by the space 92 between the second end 64 of the first mandrel 60, and the bottom of the depression 80 in the second bobbin mandrel 60. The next coil bobbin 18 may then be telescoped over shaft 40 and over the second bobbin mandrel 60', and the steps of telescoping bobbin mandrels and coil bobbins over shaft 40 are then repeated until the desired number of coil bobbins are assembled on the shaft. Then, as shown in FIG. 5, a suitable washer member 94 is telescoped over shaft 40 to provide circumferential support for flange 96 of the last coil bobbin, and nut 52 is threadably engaged with the threads 15 on the end of shaft 40, to snugly compress the column of bobbin mandrels and coil bobbins between stop 54 and nut 52.

Winding mandrel assembly 90, which holds a plurality of coil bobbins while electrical coils are wound thereon, has many advantages over winding mandrels of the prior art. its manufacturing cost is less than that of the wedge-type mandrel 10 shown in FIG. 1, and assembly and disassembly of mandrel may be easily and quickly performed by an operator, without danger of breaking the bond between the flange members and winding tubes of the coil bobbins. Instead of providing a frictional force which tends to separate the flange members from the winding tube, inherent in the prior art wedgetype mandrel, mandrel 90 provides a compressive force which tends to force the flange members and winding tube more tightly together at their bonded joints. Further, winding mandrel 90 provides complete circumferential support for both flange members of each coil bobbin, with the support starting immediately adjacent the openings in the flange members, and extending radially outward for any desired distance. The flange members are thus braced against outward movement thereof while the coil turns are wound on the coil bobbins, preventing the bulging" or outward bending of the flange members which might occur during winding of the coils if the flanges are only partially supported. Finally, winding mandrel 90 provides a uniform axial support for the coil bobbins and flanges throughout the dimensional tolerance of the longitudinal length of the coil bobbins.

Since numerous changes may be made in the abovedescribed mandrel and different embodiments'of the winding mandrel may be made without departing from the spirit of applicants invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative, and not in a limiting sense.

We claim as our invention:

'11. A winding mandrel assembly for holding a plurality of coil bobbins of the typewhich have first and second flange members and a substantially rectangular tubular member which interconnects the flange members, comprising:

a plurality of bobbin mandrels each having first and second ends and a substantially rectangular opening which extends between its ends, each of said bobbin mandrels having first and second axially adjacent, substantially rectangular portions which start at their first and second ends, respectively, with the lateral dimensions of said first portion exceeding those of the second portion to provide a step at their junction,

a substantially rectangular shaft,

said plurality of bobbin mandrels being disposed on said shaft member with like orientation, with the second portions of the bobbin mandrels being sized to snugly hold the tubular member of a coil bobbin and. having an axial length greater than the axial length of the coil bobbin, the step at the junction of the first and second sections of the bobbin mandrel and the first end of the next adjacent bobbin mandrel providing support for the first and second flange members respectively of a coil bobbin, the first end of each bobbin mandrel having a substantially rectangular depression of predetermined depth surrounding the opening, said depression being sized to receive the second end of another bobbin mandrel to provide support for the flange members of the coil bobbins while compensating for dimensional tolerances in coil bobbin length.

i i i I! i 

1. A winding mandrel assembly for holding a plurality of coil bobbins of the type which have first and second flange members and a substantially rectangular tubular member which interconnects the flange members, comprising: a plurality of bobbin mandrels each having first and second ends and a substantially rectangular opening which extends between its ends, each of said bobbin mandrels having first and second axially adjacent, substantially rectangular portions which start at their first and second ends, respectively, with the lateral dimensions of said first portion exceeding those of the second portion to provide a step at their junction, a substantially rectangular shaft, said plurality of bobbin mandrels being disposed on said shaft member with like orientation, with the second portions of the bobbin mandrels being sized to snugly hold the tubular member of a coil bobbin and having an axial length greater than the axial length of the coil bobbin, the step at the junction of the first and second sections of the bobbin mandrel and the first end of the next adjacent bobbin mandrel providing support for the first and second flange members respectively of a coil bobbin, the first end of each bobbin mandrel having a substantially rectangular depression of predetermined depth surrounding the opening, said depression being sized to receive the second end of another bobbin mandrel to provide support for the flange members of the coil bobbins while compensating for dimensional tolerances in coil Bobbin length. 